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Cascaval D.,Technical University Gheorghe Asachi | Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi
Environmental Engineering and Management Journal | Year: 2010

The influences of the pH-gradient between the feed and stripping phases and of carrier concentration inside the membrane phase on the efficiency of facilitated pertraction of nicotinic acid with Amberlite LA-2 from aqueous solution have been analyzed. The experiments have been carried out using an U-shaped pertraction cell which allowed to easily maintaining the liquid membrane between the two aqueous phases. On the basis of the experimental data and theoretical investigation on pseudosteady-state regime, a model describing the acid accumulation inside the liquid membrane by means of the permeability factor has been developed. The proposed models offer good concordance with the experimental data and can be useful for facilitated pertraction optimization.


Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Lupasteanu A.M.,Technical University Gheorghe Asachi | Turnea M.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Cascaval D.,Technical University Gheorghe Asachi
Environmental Engineering and Management Journal | Year: 2010

This paper develops the previous studies on the transfer processes and biochemical reaction kinetics involved in the bioethanol production by immobilized S. cerevisiae cells using a bioreactor with mobile beds of biocatalysts. Although the immobilization of cells or enzymes offers a lot of advantages compared to the free ones, it induces the appearance of the internal diffusion of substrate or product, with negative effect on the overall biochemical process. In the investigated case, the influences of the substrate internal diffusion on physical and biochemical processes have been quantified by means of the Biot number, Thiele modulus and reduction factor λ. The biocatalyst particles size and volumetric fraction exhibit significant and different influences on these three parameters. The increase of particle diameter led to the increase of Bi number, to the decrease of Thiele modulus and to the decrease of factor λ, but the influence of biocatalysts concentration is favorable for all discussed parameters.


Cascaval D.,Technical University Gheorghe Asachi | Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Kloetzer L.,Technical University Gheorghe Asachi
Separation Science and Technology | Year: 2012

The influences of extractants concentrations and solvent polarity on the efficiency of folic acid separation by synergic extraction with Amberlite LA-2 and di(2-ethylhexyl) phosphoric acid (D2EHPA) mixture have been analyzed. The results indicated the formation of an interfacial compound which includes one molecule of folic acid and one of D2EHPA, the hydrophobicity of this compound being increased by solvation with Amberlite LA-2 molecules. The number of aminic molecules participating in the interfacial complex formation is controlled by solvent polarity and D2EHPA concentration, decreasing from 3 to 1 with the increase of these two parameters. The results indicated that the most important synergic effect corresponds to the extractants mixture dissolved n-heptane, at low D2EHPA concentration in the organic phase (5 g/l). © 2012 Copyright Taylor and Francis Group, LLC.


Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Postaru M.,Technical University Gheorghe Asachi | Cascaval D.,Technical University Gheorghe Asachi | Kloetzer L.,Technical University Gheorghe Asachi
Solvent Extraction and Ion Exchange | Year: 2013

Formic, acetic, and succinic acids have been selectively separated from their mixture obtained by A. succinogenes fermentation using facilitated pertraction with tri-n-octylamine (TOA). This technique allows recovering formic and acetic acids from the mixture, the feed phase raffinate containing only succinic acid. The pH-gradient between the feed and stripping phases, carrier concentration in liquid membrane, and mixing intensity of the two aqueous phases control the selectivity of acids pertraction, TOA concentration exhibiting the most important influence. At pH-value of feed phase 2, pH-value of stripping phase 10, rotation speed 500 rpm, the maximum selectivity factor (S = 133) was reached for the carrier concentration 70 g L-1. © 2013 Copyright Taylor and Francis Group, LLC.


Casicaval D.,Technical University Gheorghe Asachi | Positaru M.,Technical University Gheorghe Asachi | Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Kloetzer L.,Technical University Gheorghe Asachi | Blaga A.C.,Technical University Gheorghe Asachi
Industrial and Engineering Chemistry Research | Year: 2013

Propionic, acetic, and succinic acids have been selectively separated from their mixture obtained by P. acidipropionici fermentation using facilitated pertraction with tri-n-octylamine (TOA). This technique allows the recovery of acetic and succinic acids from the mixture, the feed phase raffinate containing only propionic acid. The pH-gradient between the feed and stripping phases, the carrier concentration in the liquid membrane, and the addition of 1-octanol control the selectivity of acids pertraction, with TOA concentration exhibiting the most important influence. In the absence of 1-octanol, at a pH-value of feed phase = 2, pH-value of stripping phase = 10, the maximum selectivity factor (S = 25) was reached for the carrier concentration 70 g L-1. By 1-octanol addition, at the same pH-values of the aqueous phases, the maximum selectivity factor (S = 19) was reached for lower carrier concentration, namely 50 g L-1. The reduction of the selectivity factor for the pertraction system containing 1-octanol is compensated by diminishing the material consumption required for separation. © 2013 American Chemical Society.


Cascaval D.,Technical University Gheorghe Asachi | Postaru M.,Technical University Gheorghe Asachi | Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Kloetzer L.,Technical University Gheorghe Asachi
Canadian Journal of Chemical Engineering | Year: 2013

Succinic acid has been pertracted with TOA using free liquid membranes without or with 1-octanol. The addition of the alcohol led to the increase of up to 2.8-3 times of the acid's initial and final mass flows. At the same time, the influence of 1-octanol on the transport capacity of the pertraction system was negative, its addition inducing the accumulation of succinic acid into the liquid membrane. A mathematical model describing the acid accumulation inside the liquid membrane has been developed for pertraction systems without and with 1-octanol and offers good concordance with the experimental data. © 2012 Canadian Society for Chemical Engineering.


Postaru M.,Technical University Gheorghe Asachi | Carlescu A.,Technical University Gheorghe Asachi | Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Cascaval D.,Technical University Gheorghe Asachi
Environmental Engineering and Management Journal | Year: 2012

The reactive extractions of propionic acid with TOA dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, n-heptane) without and with 1-octanol as phase modifier have been comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant is controlled by the organic phase polarity. In absence of 1-octanol, the structures of the extracted complexes are RCOOH.Q2 for dichloromethane and butyl acetate, respectively (RCOOH)2Q4 for n-heptane. These structures are modified by adding 1-octanol and become RCOOH.Q for extraction in dichloromethane or butyl acetate, respectively RCOOH.Q2 for extraction in n-heptane. Although the presence of 1-octanol improves the extraction efficiency, it leads to the reduction of extraction constants for all considered solvents, influence that is more significant for n-heptane.


Corciova A.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Cascaval D.,Technical University Gheorghe Asachi
Scientific Study and Research: Chemistry and Chemical Engineering, Biotechnology, Food Industry | Year: 2011

The objectives of this study were to examine the potential of beta-cyclodextrin to improve the solubility of rutin and obtain inclusion compounds that were analyzed by different techniques: UV-Vis, IR spectroscopy, thermal analysis. The presence of β-cyclodextrin raises the content of rutin in water. The inclusion compounds were prepared by dry mixing, complexation in semisolid and liquid medium in 1:2 molar ratio rutin - β-cyclodextrin. The UV-Vis and IR analysis demonstrated the obtaining of inclusion compounds and the thermal analysis show that these compounds are more stable than the parent substance. © 2011 ALMA MATER Publishing House.


Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Kloetzer L.,Technical University Gheorghe Asachi | Turnea M.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Webb C.,University of Manchester | And 2 more authors.
Journal of Industrial Microbiology and Biotechnology | Year: 2012

This paper is dedicated to the study on external and internal mass transfers of glucose for succinic fermentation under substrate and product inhibitions using a bioreactor with a stationary basket bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the Jerusalimsky kinetic model including both inhibitory effects, specific mathematical expressions have been developed for describing the profiles of the substrate concentrations and mass flows in the outer and inner regions of biocatalyst particles, as well as for estimating the influence of internal diffusion on glucose consumption rate. The results indicated that very low values of internal mass flow could be reached in the particles center. The corresponding region was considered biologically inactive, with its extent varying from 0.24% to 44% from the overall volume of each biocatalyst. By immobilization of bacterial cells and use of a basket bed, the rate of glucose consumption is reduced up to 200 times compared with the succinic fermentation system containing free cells © Society for Industrial Microbiology and Biotechnology 2012.


Cascaval D.,Technical University Gheorghe Asachi | Turnea M.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Galaction A.-I.,Grt Popa University Of Medicine And Pharmacy Of Iasi | Blaga A.C.,Technical University Gheorghe Asachi
Biochemical Engineering Journal | Year: 2012

The external and internal mass transfers of Penicillin G in the process of its enzymatic hydrolysis to 6-Aminopenicillanic acid under competitive and non-competitive inhibitions using a bioreactor with stationary basket bed of immobilized penicillin amidase have been analyzed. By means of the Penicillin G mass balance for a single particle of biocatalysts, considering the specific kinetic model proposed by Warburton et al., mathematical expressions have been developed for describing the profiles of Penicillin G concentrations and mass flows in the outer and inner regions of biocatalyst particles, as well as for estimating the influence of internal diffusion on its hydrolysis rate. The results indicated that very low values of internal mass flow could be reached in the particles centre. The corresponding region was considered an " enzymatic inactive region" , its extent varying from 0 to 51% from the overall volume of each biocatalyst. By enzyme immobilization and using the basket bed, the rate of enzymatic reaction is reduced over 160 times compared to the process with free enzyme. © 2012 Elsevier B.V.

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